Superheater for fire-tube boilers and protective means therefor



I April 7, 1931- J. A. BARNES 1,799,669

SUPERHEATER FOR FIRE TUBE BOILERS AND PROTECTIVE MEANS THEREFOR Filed Aug. 9, 1928 JOHN ABM/v5.3 42%,W

A TTORNEYJ Patented Apr. 7, 1931 UNITED STATES PATENT. OFFICE JOHN A. BARNES, OF CHAPPAQUA, NEW YORK, ASSIGNOR TO THE SUPERI'IEA'IIIERCOM- PANY, OF-NEW YORK, N. Y., A CORPORATION OF DELAWARE SUPERHEATER FOR FIRE-TUBE BOILERS AND P ROTECTIVE MEANS THEREFOR Application filed August 9, 1928. Serial No. 298,476.

The present invention relates to superheaters and protective devices therefor. One of the most noteworthy developments of modern advanced engineering practice has been the use of high superheat in all types of boiler installations. The use of such high superheat however, presents many problems of great difficulty among which may be noted the difficulty of placing the superheater units in a position such that the desired high degree of superheat may be secured while at the same time reducing to a minimum, the danger of overheating and burning out such units.

The principal object of the present invention is to provide a new and improved construction for a superheater that will enable a high degree of superheat to be obtained and in which the superheater units or those portions thereof, which are exposed to the highest temperatures, will be effectively safeguarded against overheating. Considered from another angle, the principal object of the present invention is to provide a new and improved construction for a superheater for a fire tube boiler either of the stationary type, as for example, a Scotch marine type, or for a locomotive boiler, and to provide protective devices for those portions of the superheater units which are subjected to the highest temperatures so that the danger of injury to the tubes is reduced to a minimum.

The above and other objects of the present invention will appear more fully from the following more detailed description and by reference to the accompanying drawing forming a part hereof, wherein a satisfactory constructional example embodying the principles of the presentinvention is shown and wherein Fig. 1 is a somewhat diagrammatic illustration in longitudinal cross-section through a portion of a fire tube boiler showing a superheater installation therein, and Figs. 2 and 3 are enlarged sectional details of protective devices for the superheater units.

As shown in the drawing, the numeral 10 indicates the combustion chamber of a boiler and the numeral 11 the fire tubes thereof. Extending through the fire tubes are the superheater elements or units 12, 13, 14 and 15.

In order to obtain the desired high degree of superheat, certain of the superheater units,

for example, the units 13, 14 and 15, are extended beyond the flue sheet 16 and the ends of tubes 11 so as to project into the combustion chamber and into immediate contact with high temperature gases. In order, however, that such projecting portions of the superheater tubes will not be subjected to the too intense heat from the furnace, protective devices or shields 17, 18 are interposedbetween them and the furnace.

In the particular example disclosed, each of the shields 17 and 18 is in the form of a shallow trough-like member,the bottom of which is placed against the bottom wall of the superheater unit and the side walls of which are curved upwardly about the side walls of the superheater tubes. Adjacent to each end thereof, the shields 17, 18, have their side walls extending to form a pair of narrow securing straps 19 each of which is curved about a portion of the top of the superheater tubes and serves to hold the shield securely in position thereon.

I have shown the shield 17 '(see Figs.

'1 and 3), as projecting a slight distance into the end of the fire tube and as provided at its inner end with a pair of laterally projecting lugs 20, the ends of which .are adapted to contact with the interior of the fire tube 11 and which serve to hold the superheater units in properly spaced relationship within the interior of said fire tube. Instead of hav ing the shield project into the interior of the fire tube and providing it with the lugs 20, the inner end of the shield may terminate at the endof the fire tube, in which case the lugs 20 may be dispensed with; such a shield is indicated by the reference character 18.

By extending the ends of the superheater units into the combustion chamber, as shown, the desired high degree of superheat can readily be secured, while the-position of the shields 17, 18 protect such ends against being subjected directly to the too intense heat prevailing in the combustion chamber. It will be noted that the shields are of very simple construction and therefor it will be obvious that they can be manufactured at a very low cost. The installation of the shields can be quickly and readily aifected as they can be slid longitudinally over the projecting ends of the superheater units after the latter have been placed in position.

In the drawing four banks or rows of superheater units have been shown, the lowermost banks projecting into the combustion chamber and being provided with the shields of the present invention. It will be understood however, that any desired number of banks of superheater units may be employed and that the shields may be used on as many of the banks or rows of the tubes may be required. Certain of the superb-eater units in the upper row, or rows, may, if desired, be located entirely within the fire tubes, for example, the tubes 12, as shown do not have their ends projecting into'the combustion chamber. It is not therefor necessary to provide sucl tubes with'the protective shields.

It will be understood that the pi sent disclosure is to be merely illustrative and not as limiting the invention the specific constructional details illustrated and that many changes, variations and modifications may be resorted to without departing from the principles of the invention.

1. The combination with a fire tube boiler, of a plurality of superheater units located within the fire tubes of said boiler, certain of said units projecting beyond the ends of said fire tubes and into the combustion chamber of the boiler in order to insure a high degree of heating of said units, and a plurality of protective shields secured upon such projecting ends of said superheater units and extending lengthwise thereof, at least, into proximity to the ends of said fire tubes, said shields covering the wall of said units on theside thereof facing the furnace while leaving the side of said wall facing away from the furnace uncovered.

2. A protective shield adapted to be secured upon a projecting portion of a superheater unit located within a fire tube boiler,

- said shield being in the form of a shallow trough-like member adapted to extend lengthwise of and cover the bottom and the side walls of a pair of adjacent lengths of a superheater coil or unit, and said shield being provided with a pair of strap-like lugs for engagement with the top wall of said unit to hold the shield securely attached thereto.

3. A protective shield adapted to be secured upon a projecting portion of a superheater unit located within a fire tube boiler, said shield being in the form of a shallow trough-like member adapted to cover the bottom and the side walls of a pair of adjacent lengths of a superheater coil or unit, and said shield being provided with a pair of strap-like lugs for engagement with'the top wall of said unit to hold the shield securely attached thereto, and said shield being side wall of a superheater coil or unit, and

said shield being provided with a pair of strap-like lugs for engagement with the top wall of said unit to hold the shield securely attached thereto.

5,, A protective shield adapted to be .se-

cured upon a projecting portion of a super- 7 heater unit located within a fire tube boiler, said shield having a wall adapted to extend lengthwise of and engage with the wall of said unitto cover the side thereof facing the furnace and to cover the terminal end of said unit, While leaving the side of the wall of said unit facing away from the furnace uncovered, and said shield being further provided with means for securing it in position 1 upon said unit.

In testimony whereof I have hereunto set my hand.

JOHN A. BARNES. 

